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Thymic Tumours

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Thymic Tumours ICD‐O‐3 C37.9 Rules for Classification The classification applies to epithelial tumours of the thymus, including thymomas, thymic carcinomas and neuroendocrine tumours of the t­ hymus.

It does not apply to sarcomas, lymphomas and other rare tumours.

This classification is new to the 8th edition and is based upon recommendations from the International Association for the Study of Lung Cancer (IASLC) Staging Project and the International Thymic Malignancies Interest Group (ITMIG) (see references).1–3 There should be histological confirmation of the disease and division of cases by histological type.

The following are the procedures for assessing T, N, and M categories: T categories Physical examination, imaging, endoscopy, and/or surgical exploration N categories Physical examination, imaging, endoscopy, and/or surgical exploration M categories Physical examination, imaging, and/or surgical exploration

Regional Lymph Nodes The regional lymph nodes are the anterior (perithymic) lymph nodes, the deep intrathoracic lymph nodes and the cervical lymph nodes.

T – Primary Tumour TX Primary tumour cannot be assessed T0 No evidence of primary tumour

T1 Tumour encapsulated or extending into the mediastinal fat, may involve the mediastinal pleura.

T1a No mediastinal pleural involvement T1b Direct invasion of the mediastinal pleura T2 Tumour with direct involvement of the pericardium (partial or full thickness).

T3 Tumour with direct invasion into any of the following; lung, ­brachiocephalic vein, superior vena cava, phrenic nerve, chest wall, or ­extrapericardial pulmonary artery or vein.

Lung, Pleural, Thymic

TNM Clinical Classification

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Lung, Pleural, and Thymic Tumours

T4 Tumour with direct invasion into any of the following; aorta (ascending, arch or descending), arch vessels, intrapericardial pulmonary artery, myocardium, trachea, or oesophagus

N – Regional Lymph Nodes NX N0 N1 N2

Regional lymph nodes cannot be assessed No regional lymph node metastasis Metastasis in anterior (perithymic) lymph nodes Metastasis in deep intrathoracic or cervical lymph nodes

M – Distant Metastasis M0 No pleural, pericardial or distant metastasis M1 Distant metastasis M1a Separate pleural or pericardial nodule(s) M1b Distant metastasis beyond the pleura or pericardium

TNM Pathological Classification The pT and pN categories correspond to the T and N categories. For pM see page 8.

Stage –THYMUS TUMOURS Stage I Stage II Stage IIIA Stage IIIB Stage IVA Stage IVB

T1 T2 T3 T4 Any T Any T Any T Any T

N0 N0 N0 N0 N1 N0, N1 N2 Any N

M0 M0 M0 M0 M0 M1a M0, M1a M1b

References 1 Nicholson AG, Detterbeck FC, Marino M, et al. The IASLC/ITMIG thymic epithelial tumors staging project: proposals for the T component for the forthcoming (8th) edition of the TNM classification of malignant tumors. J Thorac Oncol 2014; 9: s73–s80.

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Lung, Pleural, Thymic

2 Kondo K, Van Schil P, Detterbeck FC, et al. The IASLC/ITMIG thymic epithelial tumors ­staging project: proposals for the N and M components for the forthcoming (8th) edition of the TNM classification of malignant tumors. J Thorac Oncol 2014; 9: s81–s87.

3 Detterbeck FC, Stratton K, Giroux D, et al. The IASLC/ITMIG thymic epithelial tumors staging project: proposal for an evidence‐based stage classification system for the forthcoming (8th) edition of the TNM classification of malignant tumors. J Thorac Oncol 2014; 9: s65–s72.